Elongation of the BH8 beta-hairpin peptide: Electrostatic interactions in beta-hairpin formation and stability

Citation
M. Ramirez-alvarado et al., Elongation of the BH8 beta-hairpin peptide: Electrostatic interactions in beta-hairpin formation and stability, PROTEIN SCI, 10(7), 2001, pp. 1381-1392
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
PROTEIN SCIENCE
ISSN journal
0961-8368 → ACNP
Volume
10
Issue
7
Year of publication
2001
Pages
1381 - 1392
Database
ISI
SICI code
0961-8368(200107)10:7<1381:EOTBBP>2.0.ZU;2-K
Abstract
An elongated version of the de novo designed beta -hairpin peptide, BH8, ha s allowed us to gain insight into the role of electrostatic interactions in beta -hairpin stability. A Lys-Glu electrostatic pair has been introduced by adding a residue at the beginning and at the end of the N-terminal and C -terminal strands, respectively, of the beta -hairpin structure, in both or ientations. The two resulting peptides and controls having Ala residues at these positions and different combinations of Ala with Lys, or Glu residues , have been analyzed by nuclear magnetic resonance (NMR), under different p H and ionic strength conditions. All of the NMR parameters, in particular t he conformational shift analysis of C alpha protons and the coupling consta nts, (3)J(HN alpha). correlate well and the population estimates are in rea sonable agreement among the different methods used. In the most structured peptides, we find an extension of the beta -hairpin structure comprising th e two extra residues. Analysis of the pH and salt dependence shows that ion ic pairs contribute to beta -hairpin stability. The interaction is electros tatic in nature and can be screened by salt. There is also an important sal t-independent contribution of negatively charged groups to the stability of this family of beta -hairpin peptides,